The film, opening in theaters on November 5, documents the outing of CIA operative Valerie Plame by Bush administration officials, and the attacks on her husband, former Ambassador Joe Wilson.

Academy Award winner Sean Penn was Liman's first choice to play Wilson, and while getting him on board proved challenging, it wasn't impossible thanks to Naomi Watts, Liman's first choice to play Plame.

"I said [to Watts] 'Sean Penn is our first choice. I know you did two movies with him. Do you keep up with him?' She said yes. 'Would you make the same call to Sean Penn that Jez Butterworth ['Fair Game' screenwriter and co-producer] made to you and ask him to read 10 pages?' And by the next week I was having lunch with Sean Penn."

Liman, speaking to an audience at a pre-screening of the movie on Tuesday in Silver Spring, Maryland, said that Watts herself wasn't so quick to sign on. When approached to read the script, she said no.

"She said, 'I'm literally not reading anything right now. I just gave birth.' Jez said, 'please, just read 10 pages,'" Liman recalled. "Of course she called him back two hours later and said she couldn't put it down and that she loved it. And 10 days later we were meeting and she was breast feeding in my office."